At what frequency do breadboards become a bad idea for analog prototyping? I am considering using vector boards and soldering parts directly to the circuit board. Thanks
I made quite a lot of prototype boards using Verowire along Verocombs (see example below) back in the day, usually centred around microcontrollers/microprocessors with external RAM and EPROM. We found through practical experience that you couldn't really go above 20 MHz digital signals in such a circuit.
This isn't the same as what you have but hopefully similar enough for guidance.
I worked with a guy who developed 45MHz IC [IF amplifier/PLL/synchronousdemod for NTSC video]. He and supertech breadboarded it, atop sheets of copper. Why? The SPICE models were not adequate. The compute power was not adequate.
They worked in a screenroom.
Result? the recovered video was identical to a Philipps Video/RF generator with DOT or Greyscale or ColorBars modulation.
Why? the fully differential silicon circuits, the GroundPlane I used to build the PCB prototype, and the synchronous-demod/PLL he used.